This is what the French anthropologist Olivier Roy calls “holy ignorance.” It is not a failure of intelligence, but a proud refusal to know things tainted by the arrogance of inevitability. He writes: “There is a close link between secularization and religious revivalism, which is not a reaction against secularization, but the product of it. Secularism engenders religion.” The defenders of the lost cause feel persecuted, and the more support there is for their opponents, the grander they are in their lonely war.
I would refine this to say that secularism engenders a reactionary retreat into religion on the part of some who can't stand the idea that the world is bigger than their particular system of spiritual indoctrination. Not everyone who believes in something does this, and I'm not entirely certain it's an inevitably by-product of belief systems as such.
I do believe it's a by-product of a specific kind of belief system, one that refuses to recognize the need for both secular and sacred space as parallel and necessary projects. To go back to Brad Warner: you need faith to keep you going, and doubt to keep you from going off the deep end. But if you start by being off the deep end to begin with, it seems there's little chance of you coming back.
What's really dangerous is when one of the stated missions of such belief systems is rejecting those parts of material reality that are most essential to your survival. Or, for that matter, to the survival of the species. It's gloomily ironic that one of the belief systems that is enlisted most fervently in the defense of such short-sighted behavior is the one that exalts poverty and charity as its highest ideals. What happened, guys?